I am not a breeder and dont intend to breed ever. Just thinking about it scares me to death

I have been reading this thread and it is fascinating about how and why and why not etc etc.
Just a question regarding the dog who is 12 pounds
Could it be that he is the right "frame" as far as physical size go's in regards to height and length etc but is over weight by six pounds.? Would that make a difference to how big the pups are? Would it mean that the pups would be bigger if he is maybe over weight ?
Just a question and was curious.